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(ModeL) 4Sheets-Qheeti.

11 M. ROOTS.

ROTARY BLOWER. v N0.24'7,691. Patented Sept. 27,1881.

(Model) 4 Sheets-Sheet 2.

F. .M. ROOTS. I ROTARY BLOWER.

Patented Sept. 27

(Model) 4 Sheets-Sheet 4 F. M. ROOTS.

I ROTARY BLOWER. No. 247,691 fPatented Sept. 27,1881.

est; Xnuefiorthe pistons to their fifth, to protect the ssis s FRANCIS iii. ROOTS, OFOGNNERSVILLE, ENDIANA.

WDTARKfi horses.-

SPEGXEIOATION forming part of. Letters lPstent Ho. 2%7591, dated September 27, 1881. Application flied Mex-c119, 1880. (Model) To all whom'z't may concern:

Be it known that I, FRANCIS M. Roors, of Oonners\"illc, Fayettc county, State of Indiana, have invented certain new and useful Improvements in Rotary Blowers, of which the following is a specification.

My invention relates to rotary blowing-engines in which two or more rotating abutments coact together and with the shell in which they are incased to force a current of air or other fluid in one direction without permitting back ward. escape of the-same under pressure.

The objects of my improvements are, first, to insure perfect contact ofthe abutments with each other during their entire revolution, so that there can he nb bnckward escape of the fluid .fiictetLiipon-fiseemrd to-rm duce the friction between the necessary points of contact, avoid concussion in use lessen the" surface necessary to be finished, and save ma.- terial; third, to provide a means to pack the ends or tips of the pistons, so as to secure perfeet contact between them andtho shell when the machine is to be used under heavy pressnre, or as a pump or hydraulic engine; fourth, to facilitate the readjustment of the abutnlents and replacement of thejournul-linings to bring proper relative position;

abutments and inside of the shell against injury by extraneous substances entering the induction-port sixth, to facilitate the removal of the gear-wheels and the housing in which they are incased. I at tain these objects by the mechanism illustrated in the accompanying drawings, in which- Figure 1 is a long tudinal vertical section of a. machine embodying myimprovements, takenthrough the line roof Fig. 2, which is a,.centrei vertical transverse section of the machine. Figs. 3 and 4 are similar sections, showin g the sbntments in different positions. Fig. 5 is an end elevation of my improved cog-wheel. Fig. 6 is an axial section of one of the aontments fitted with the templets preparatory to dressin g the convex a-rcs'a-nd concave points of contact. Fig. 7 is an end elevation of the mechanism for dressing the abutments. Fig. 8 is a diagram illustrating my system for obtaining the centers from which the convex arcs and concave points of contact are. described. Fig. 9 is a perspective view of my improved c 'iistrueted.

are the pitch-line circles.

- viding-line, mac, and the angles to it.

journal-bearing. Fig. IO-is a teen view, in perspective, of the lower box and i'ts lining; and Fig. 1.1, a similar view of the cup and lin ihg. Fig. 12 is a front elevation of the inner plate of the gear-wheel housing.

Similar letters refer to the same parts throughout the several views.

The case or shell of the blower'cousists of, two semi-cylindrical flanged shells, A, secured between end plates, B. (l O are the coactingrotating' abutments, mounted one above the other within the case A.

The method of constructing my improved abutments is as follows The abutment-shafts D D are placed the requisite distance apart, depending upon the size of the machine to be Two squat circles are'descriiieii from the siiaft'ceuters by n. radius equal to half-the distnnce'bctmeirsaid centersf'lhese These circles are divided into eight equal parts by radizii lines, one of the dividing-lines a: cc nessingthrongli the centers of both shafts. Within each of these circles, and described from the same cenmm, are two smaller circles, usually about on etwell'th less in diameter than the pitchcircles, although the size of the inscribed circles mny be varied without materially affecting the result. 'lhnsfnr the steps taken are the same as in the patent No. 58 ,745, granted to P. H. Roots October 9,1866, but the eonvexarcs' and concave snrfuccs'in that case were respectively described from points in the centred diradial line 3/ y, at right I have discovered that in order to, insure perfect contact during the entire revolution the radius by which the convex surfaces and concave points of contact are described must extend across the control dividing-line, as, to a point within the pitch-circle. l

The points from and the radius by which the convex surt'acesnnd the concave'points of contact in my improved shutting pistons are described I obtain as follows, (-retering now particularly to the diagram, Fig. 8:) From the point t, where line :0 cuts the inscribed circle,

I'draw a line to a point, i where line 2 intersects the pitchcircie. 'ihen, by a. radius equal tonne-fifth of the line just obtaineci,-a.nd with one point of the compass on point i, (in line w pistons become worn. When used for this purside of the central contact-point, c, are out also serve without other packing to keep up and the inscribed circle,) I obtain two points,

'5 in the inscribed circle equidistant from line "i as. From these points i" as centers the oppo- J site arcs of the pistons are described by a radius, 7', extending from point i acrossline a: to point B, where line .1 cuts the pitch circle. With this radius 1'- all the convex surfaces, as well as all the concave points of contact, are described from centers i as when the abutments are in the position shownin the diagram (their respective dividing-lines w :0 at right angles to each other) the convex arcs of one abutment are in perfect contact with the concave contact-points in the other.

I do not limit myself to the exact location described for point i as this point may be somewhat varied without departing from the principle of my invention. 7 v

The extreme ends of tips 0 of the pistons are described from the shaft-centers. Coa'cting abutments thus constructed will maintain perfect contact with each other during the entire revolution, as appears clearly from Figs. 2, 3, and 4. The ends of the pistonsnpon each away, and the concaves between the concave abuttingpoints are cut back, thus leaving onlythe requisite surface to keep the contact during the revolution of the abutments. 1 thus reduce the surface which requires finishing more than three-fourths, effecting a great saving of labor and material, giving more clearance to the parts, and greatly reducing the friction, and when the machine is used as a pump for water or denser fluids it will operate without concussion. When used for thispurpose or as a wator-meter or hydraulic engine it is desirable that the contact between the pistons and the case should be perfect. In Figs. 2, 3, and 4 is shown a means by which this end is accomplished. A packing-strip, 0, of leather, rubber, or other suitable material, is clamped between a metal retaining-strip, c and the tip of the piston by screw bolts. The strip may contact with-the case should the ends of the pose the bolts should pass through transverse slots in the metal strip to admit of its .radial adjustment.

To attain the best results, great accuracy is required in fitting the parts together, in order that the abutment-shafts may be given and maintain the proper relail e position to each other. Any change in the relative position of the shafts to each other or the case, either as to parallelism orcireumferentiall y, will impair the effectiveness of the machine. Heretot'ore the labor of adjusting the pistons in the first place' and readjusting them when the bearings became worn from use has been difficult and tedious, requiring great skill and care. By my present improvements these difiiculties are in .permit free play of a great degree obviated.

I have provided means to prevent the driv;

ing-shaft from being drawn ,out of line by the l dredth of an inch in (BllSlOH of the driving-belt, by providing a rigid bearing for the end of the driving-shaft outside of the driven pulley.

Depending from the table which supports the journal-boxes is a plate, E, eastv with the end plate of the blower-ease, ported by. brackets E, alsoeast with the end of the case. The plateE is planed otf parallel with theinside of the end plate.

F is an iron frame, having upon its outer end arable to support journal-box. The shape of the frame in vertical cross-section is semi-cy- .lindrical.

the belt from the countershaft. The inner end of the frame F is planed and rigidly sup- 1t hasopenings of sufficientsize to: V

to accurately fit the plate E, to which it is se curely bolted. After it has been properly adjusted and secured in place on the end of the case, tapering holes are bored through the plate E and the end of frame F, to receive tapering steady-pins a. By means of these pins as guides the frame F maybe removed when desired and readily replaced in its original position. This frame gives arigid support to the shaft outside of the pulley.

I have also made provision to quickly readjust the shafts D. in lihe should their journalbearings become unevenly worn. This I accomplish by the devices illustrated in Figs. 9, 10, and 11.

'The journal-boxes G G are bored out exactly concentric with the axes of revolution.

The linings H are turned on upon the outside to fit the boxes, and on the inside bored to fit the journals, thus leaving the shell-linings of uniform thickness in cross-section. So constructed, the linings may be turned around in their boxings and be evenly worn all around, and when so much worn as to require replacing, the cap G is removed,- slipped around the shaft, and s new lining made to follow it while being removed, thus restoring the original position of the abutments. A set-screw may be passed through the top G of the box to prevent the linings from slipping.

It is evident negligence (notkeeping the parts properly lubricated) the teeth of the gear-wheels will become worn and permit the abutment to lag.

In Fig. 5 is shown an arrangement to compensate for the wear of the teeth and facilitate the adjustment of the abutments when fitting up the machine. By this means the abutment may be advanced or retracted in its path of travel around its shaft. This object I-accomplish by means of a cog-wheel consisting of an outer rim, I, and an inner hub, J, accurately fitted together. The keyway in the hub is out just wide enough to fit the key, while the keyway in the rim I is out about one-sixteenthgr one-eighth of an inch lar r.. The spaces between the key and the si es of the keyway in the rim are filled with thin strips of rolled iron or steal from one sixty-fourth to (menusthickness, The aimcan 'the old lining eeeieea .i

3 11113 be circumfer'entially adjusted. upon its hub by changing one or more of. these strips from one side to the other of the key.

In use the pistons and interior oi' the shell are liable to be injured hyexirnnoous substances being drawn into the inductiouport.

Attempts have been made tov overcome this ditficulty by covering the port' witha wire 7 gauze screen; but it-isfound then substelices upon it is, or wili be, carrie'lloufohm line oi" draft. The'port is also guerdcd by a graie,i.-, ioceted within the hood. Shonid any substance get within the hood its passage to the machine wiiibe obstructed. 7

My improved housing for protecting the gear-wheelsisconstructed'esfoilows: Fianges -G arenas; upon the outer end of the journalboxes G.

plate. The inner plate, M, of the housing is divided verticeiiy in the plane of the axes of the two shafts D i). i s-has cast upon it projections n,oorresponding to. the flanges G These projeciions ere pinned ofl true to it the flanges, end the plate is secured in the positionehown in Fig. 1 by screws passing through the flanges G into the projections The sbeii N of the housing is secured to pinte M byscrews passing through the piete and into the in weirdly-projecting flange upon the rim of 'shell N. The purpose of this arrangement is to faciiit-nte the removal of the cog-wheeie or of the housing without disturbing the cogs. This iseccoinpiished by removing the sheil N, taking out the screws in flange G and removing the divided hock plat-e, M. The keys are now easily accessible from the hack, and the cogs may be readiiy taken off or the rim of the ndjnstahie'cog-wheei-set around upon its hub. I wili now-describe the method by which my improved abutinents are accurately dressed.

Foreach size'of abutment 1 construct two tempietsP P, according to the formula given for constructing any; cbutmeut's. pletsnredressed "to the-exact size and shape ot a cross section of the abutment.

Through ihese clnmping-bnits'q are passed.

The shafts and the ends of the abutments bein g turned down true, the tern piets are slipped over the shafts upon each end of the-abutment,

and theeinrnpin bolts passed through the ten pietsendt-he no! ow abutmenis. Thetemplete toolerge in pass ih'roueh themesliinwoulrifhe birthehoodeiif porn-K;

(See Fig:;. I, ihand lii.) .[jheee eretu'rned oii peraiici with the inside oi the These tein- The four centersineach templei; from which the peripheore adjusted cxni-iiy v; lgr-ositr cnch other and out of wind, and the abutment. iie'hiiy clamped between them. 'iheabutmcnt is then mounted in standards R on the hell oi the pinncr, (see Fig. 7,) the jonrnnhpios p of the teniplcls resting in V-nhnpod bearings and held in plaoehy caps. The opposite tip of the piston is clamped .ini;he emi oi' a yoke. s. which is jointed ion traveling nut. S, upon ii screw, '1. The lower conical end of tho :ci'ew rests in a. step, t, on the hed-pinie'oi' the machine. iv this screw ii-iii its out the abutment is turned upon the 'pin g2, and the convex surface of the piston fed to ihe onitineti'aoi and dressed down to the 'iempiets. The concave contact-points, being cniy sbnni-cne-ionrt-i'a to one-half inch in Width, are dressed iicwn io hhe teznpleis l y e tooi oi' prcpcrsiiape, While the abutment remains sin.- tionnry in standards B. When oncof the con vex arcs and one oi the concave points are dressed the abutment is removed fromv the standards R, the pins p changed to other holes inthe templets, and the abutment replaced in the standards preparatory to dressingonother eigili the name ne The operation is rep eted until aii the convex arcs and concave contactrpoints are dressed down to the tempiets. ihnvedeecribed in fmethodofdreesingniyiinproved piston ehutments uponan iron piener; butt-hey may niso be dressed upon a miilingmeohine or other dressing-tool in snhsinntinily the same Way, as the principal fen-sure in mymethod is the centering of abutinents upon the points i from which the arcs sire described,or melting the edge of the cutiingi'ooldescribe an are from sni d centers, or around them, as an axis. I

It is also evident that, instead-of the pine'p, a. shaft may he passed through the pinholes, or center hearings may be made in the tem pleiss at said points i,to receive centeringpoints secured in the standards R.

My improved abutments are bored outhoi low.'and are cast with the shafts in position.

By my improvements I am enabled to construct a blower entirely of metal as chenpiy as thoseheving wood-covered abutments; and as myimproved blower will not be afiected by different conditions of atmospher ordinary vadescribed, and illustrated in Figs. .6 and 7;, is

not claimed herein, as I' intend to maike the method of finisbing'the subject offa. separate application.

I claiml. Ahutinents forrotary pressureblowers, constru ted substantially as described-that is, having the convex arcs of the pistons and.

the concave points of its recesses described from it point, as 1', within the pitch-circle by arsdius extending from said point i across the central dividing-line a; to a point, i, in the pitch-circle.

"2. Abutments for rotary blowers having their convex arcs and concave points of contact described substantially as hereinbefore set forth, and having the ends of the pistons upon each side of the central point, e, and their concave surfaces between the concave points of contact cut away, to lessen the friction, avoid concussion, and reduce the surface of the abutments necessary to be finished.

3. The abutments of a rotary blower, such as described, having its ends cut away upon each side of the central point, 0, in combination with a, packingstrip, c secured to one side of said centrsl tip, a, to make an air-tight' fit between the casc and piston, substantially as described.

4. In a rotary pressureblower, the combination, substantially as specified, of the coacting ahutments and their shafts with journal-boxes G G and the two-part linings H H, the bearin gs in the hoses and the interior and exterior of the linings being concentric with the axes of the shafts, so that in case of uneven wear the said abutments may be in contact byturning said linings, and the linings removed and replaced without disturbing the position of the abutr'nents.

5. The rotary pressure blower having coactingrotary abutmen ts incased and operating within the shell A B, in combination with the hooded port K and grating L,for the purpose set forth.

6. In a housing for rotary blowers, the cog; bination, substantially as specified, of th flanged journal box, the divided inner plate, M, adapted to be readily secured to or removed from said flange G: independent of the gearwheels, and the shell N, secured to plate M, for the purpose of protecting the gear-wheels and readily removing them when desired.

FRANCIS M; ROOTS.

Witnesses:

CHARLES M. COVERT, THOMAS "M. Lr'r'rLE. 

